Various structural parts, which may be formed of metal or plastic, are generally coated prior to use to protect structures from the external environment or damages, to prevent structures from corrosion, to enhance the durability of vehicle parts, and to enhance the exterior appearance thereof.
In addition to a role of coating of protecting from corrosion caused by the external environment, implementing color and esthetic effects by coatings have become more significant factors in the manufacturing process of metal structures or a motor vehicle, particularly to enhance the exterior or appearance. Therefore, to impart esthetic and luxurious appearance to the surface of a metallic structure, some efforts by adding pearls or metal component particles to the coating composition have been conducted.
Furthermore, due to recent development in the various electrical or electronic products and the vehicle industry, a coating technique has been considered significantly together with other functional, convenient or safety features of such products. In addition, the coating may be determined by customer preference, and the coating technique also may be required to regenerate a similar color or effect of the prior coating when recoating is performed for repairing the surface.
There have been simple coating compositions for implementing colors to the surface of home appliance or motor vehicle. In addition, the coating compositions to which a pearl exhibiting diffused reflection effect with metal particles is mixed, thereby generating diverse colors or esthetic effect have been developed and commercialized.
In some related art, a coating composition for coating the surface of a metal containing about 4 to 20 wt % of aluminum pieces and a method of coating the composition, in which the composition containing aluminum pieces is coated two times, have been developed. In addition, another example of coating composition which may contain a hydrophilic treated metal powder (aluminum metal powder) exhibiting a diffused reflection effect at about 0.05 to 10 wt % with respect to 100 wt % of the total coating composition has been developed. In another example, a technique to form a sparkling cutting film containing a pigment composition with aluminum pigment on the surface of an article has been developed. Moreover, a technique, for coating a motor vehicle has been reported. In such case, coating as a translucent metal oxide film, and an effect pigment, in which the distribution of particle size is adjusted to have about 9.5 μm of D10, about 20 to less than 40 μm of D50, and about 45 to less than 85 μm of D90, may implement pearl gray.
Meanwhile, in the above-described techniques, a metal component, for example, aluminum, may be contained in a coating and sparkling effect may be applied by diffused reflection produced by the metal component, such as aluminum. However, sparkling effect produced by the metal component may not be favorable, and luxurious feel with a three dimensional effect may not be obtained.
In other examples, a solvent coating composition including multilayers of an under coat layer, a metal coat layer, an over coat layer, and the like, and a manufacturing method thereof have been reported. Such coating composition may include multilayers, and improved coating property and coating durability may be improved. However, the coating may be difficult to apply and inefficient due to complicated coating procedure or materials for multi-layers, and further may cause difficulties to reproduce the same coating or effects.
As described above, since coating compositions of the conventional techniques may have limitation in producing sparkling effect or a luxurious appearance, a further improvement in coating composition is strongly desired to meet various customer needs and improve product competitiveness.
The above information disclosed in this Background section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.